Automatic firearm



May 7, 1940. M. BIRKIGT AUTOMATIC FIREARM med Api-11 1e. 193e Jhr/@IWA Q umm Bzzwgg.

Patented May 7, 1940 UNITED STATES AUTOMATIC FIREARM Marc Birkigt, Bois-Colombes, France Application April 16, 1938, Serial No. 202,546 In Belgium February 11, 1938 4 Claims. (Cl. 42-3) The present invention relates to automatic firearms and especially, although not exclusively,

to automatic quick firing guns to be mounted on aircrafts. v

5 My invention is concerned with guns of this type having a breech structure movable axially with respect to the gun tube and constituted by two elements movable axially with respect to each other, one of these elements constituting the breech block proper and the other carrying the ring pin. These two elements are provided with locking means arranged in such manner that, as long as the breech block proper lis not in firing, or front position (in which it closes the rear end of the gun tube), the two elements are interlocked, whereas, when said breech block comes into said firing position, it is locked to the Y xed casing but the firing pin carrier is released and can therefore move forward a certain distance under the effect of a counter-spring associated with the breech structure and of the inertia of the whole, whereby the firing pin can strike the cartridge.

The object of the present invention is to provide a gun of this type which is better adapted to meet the requirements of practice and, in particular, in which the firing safety is considerably increased so as to eliminate any possibility of accident.

With this main object in view, the essential feature of the present invention consists in interposing between the two above mentioned elements of the movable breech structure, elastic means for urging the firing pin carrier toward the front of the firearm, with respect to the breech block proper.

Other features of the present invention will result from the following detailed description of a specific embodiment thereof,

l A preferred embodiment of the present invention will be hereinafter described, with reference to the accompanying drawing, given merely by way of example, and in which:

Fig. 1 is an elevational view, partly in axial vertical section, of the breech mechanism of an automatic gun for use on an airplane, made according to the present invention;

Fig. 2 is a similar view of the same breech mechanism, showing other relative positions of the parts, corresponding to another time of the operation of said mechanism;

Fig. 3 is a sectional view on the line III-III of Fig. 1;

Fig. 4 is a Vertical seca: nal view on the line IV-IV 0f Fig. l;

Fig. 5 is a. partial vertical section on the line V-V of Fig. 1.

In the embodiment of my invention illustrated by the drawing, the rear part of the barrel or tube I of the gun carries, xed thereto, a breech 5 casing 2. This breech casing is provided with a cartridge feeding slot 3 at the top and another slot 4 at the bottom, for the ejection of the cartridge cases having been red.

A breech structure is mounted in said breech 10 casing and said breech structure is constantly urged toward the front, that is to say toward the rear end of tube l by a counterspring 5.

This breech structure is made of two elements relatively slidable with respect to each other in l5 the axial direction.

One of these elements, to wit 6, constitutes the breech block proper. The front end of said breech block is adapted to force and wedge the cartridges successively into the chamber of the 20 gun tube, in the usual manner.

The other breech element constitutes the firing pin carrier. Specifically, as shown by the drawing, it is constituted by two bars 9 located each on one side of the breech block 6, said bars being g5 interconnected, preferably at their front parts, by a cross piece I0, which carries the firing pin ll`.A

'Ihe breech block E carries locking means, constituted, in the example that is considered, by a 3g pawl l pivoted at its front part to said breech block and adapted to occupy either of two diierent positions, to wit an upper position (Fig. 2) and a lower position (Fig. 1).

When locking pawl 1 is in its lower position 35 it locks the breech block 6 (in the front or firing position thereof) to the breech casing 2. The top projection of the free end of pawl 1 is, in the lower position, disengaged from the recess of part 9 which terminates at 8, and therefore per- 40 mits said part 9 to slide along the breech block 6 in the frontward direction, under the eiect of the counter-spring 5 which bears against cross piece I 0 associated with bars 9. As a result of this supplementary movement of parts 9 and Il), 45 the firing pin Il carried by piece I0 strikes the cartridge.

I provide means for driving back the ring pin carrying structure 9-I0 immediately upon the firing of a cartridge. Such means may, for in- 50 stance, consist of a piston and cylinder system l2-I3 the movable part of which is rigid with a push piece |'4 adapted to cooperate with said structure 9-l0, so as to push it rearwardly under the effect of the burnt gases.

As soon as, in the course of this rearward movement, system S-IU reaches the position in which its lower recess comes. opposite pawl 1 (that is to say the position in which the end of pawl 1 is located opposite the inclined edge 8 of said recess) said pawl is allowed to pivot upwardly, under the effect of the upward component of the thrust exerted upon bevel surface I5. This unlocks the breech block 6 from the breech casing 2 and interlocks the breech block 6 and the sliding structure S-IIL The whole of the breech structure thus4 moves toward the rear, compressing the counter spring 5 until said spring first stops and then reverses this movement of the breech structure, finally bringing back the parts into their initial positions after the cartridge case has'VY been ejected and a fresh cartridge introduced into the gun chamber.

According to the essential feature of the pres,--Y ent invention, I interpose, between the elements of the breech structure, that is to say between the breech block 6 and the firing pin carrying structure 9-I0, elastic means for urging said firing pin'carrying structure toward the front of the rearm when the Ibreech block 6 is fixed in position.

With such an arrangement, during the first portion of the recoil movement of structure 9-I0, that is to say While said structure 9--l0 is moving back towardi its interlocked position with the breech block 6 (then locked in rin'g position) said structure 9--I0 is compelled to overcome the resistance of said elastic means, which then act in the same manner as the counter spring 5,.

These elastic means, such as constituted by spring I1, reduce the risks of an accidental unlocking of the breech block 6 before the proper time. Such risks are particularly serious when the gun is firing vertically since, in this position, bars 9 might, in the absence of such elastic means and under the eiect of gravity, slightly compress the counter spring 5 and produce the disengagement of the breech block before the shot has been red. Also,` in the case of hanging iire, said bars 9 might, by rebounding, accidentally produce the disengagement of the breech block 6.

' In both of these cases, a premature disengagement of the breech `block would permit the latter to recoil immediately upon the firing of the shot, when the thrust vexerted by the burnt gases through the cartridge case on the front end of the breech block 6 is considerable, thus risking deterioration of the rearm.

As such a premature disengagement of the breech block from locking engagement with the breech casing is opposed by the elastic means I1, the firing safety is greatly improved.

For practical purposes, I may emplo-y many embodiments of such elastic means, and I have found that it is advantageous to employ the specific arrangement illustrated by the drawing.

In-this case, I provide, in bars 9, slots 9 adapted to accommodate lugs I6 rigid with the breech block 6, so that said lugs can move in said slots in the course of the relative axial .displacements of said breech block and said bars. Ihe springs I1 above mentioned are mounted in said slots, being constituted by coil springs the front ends of which bear against the front ends of said slots, that is to say upon the respective bars 9, while the rear ends of said springs I1 bear againstsaid lugs I6. I'his spring arrange- S-I 0 with respect to the breech block 6.

In a general manner, while I have, in the above description, disclosed what I deem to be practical and eiilcient embodiments of the present invention, it should be well understood that I do not wish to be limited thereto as there might be changes 'made in the arrangement, disposition, and form of the parts without departing from the principle of. the present invention as comprehended Within the scope of the appended claims.

What I claim is:

1. An automatic firearm which comprises, in combination, a tube, a breechstructure movable with a longitudinal reciprocating motion in line with said tube at the rear thereof, a stationary casing rigid with said tube for guiding said breech said breech block at the end of the frontward.

movement of said breech block, whereby said ring pin carrier can further move frontwardly, said last mentioned means being adapted to act in a reverse manner upon the return movement of said firing pin carrier, means for driving back said tiring pin carrier upon the firing ofa shot, and elastic means between said breech block proper and firing .pin carrier for urging saidV firing pin carrier frontwardly with respect to said breech block.

2. An automatic rearm which comprises, in combination, a tube, a breech structure movable with a reciprocating motion in line with said tube at the rear thereof, a stationary casing rigid with said tube for guiding said breech structure, said breech structure including a breech block proper and a firing pin carrier movable longitudinally to a limited extent with respect to said breech block, cooperating means, provided on said breech structure elements and said breech casing and operative by relative displacements of said elements, for interlocking the two breech structure elements as long as said breech block has not reached its extreme position toward the front and locking said breech block in said casing when said position is reached while uncouplingsaid firing pin carrier from said breech block, whereby said firing pin carrier can further move frontwardly, said last mentioned means being adapted to have their action reversed for inverse movements ofthe breech elements, means for driving back said firing pin carrier upon the firing of a shot, and spring means between said breech block proper and iiring pin carrier for constantly urging said ring pin carrier frontwardly with respect to said breech block.

3. An automatic rearm which comprises, in combination, a tube, a breech structure movable with a reciprocating motion in line with said tube at the rear thereof, a stationary casing rigid with said tube for guiding said breech structure, said breech structure including a breech block proper and a firing pin carrier movable longitudinally to a limited extent with respect to said breech block, a pawl carried vby'. said breech block and notches` with inclined edges provided on said firing pin carrier and said breech casing adapted to cooperate successively with said pawl under the eiiect of relative movements of said breech structure in said casing for interlocking the breech block proper -and the firing pin carrier as long as said breech block has not reached its extreme position toward the front and locking said breech block in said casing when said position is reached while simultaneously uncoupling said firing 4pin carrier and said breech block, whereby said ring pin carrier can further move frontwardly when said breech block is stopped, said pawl and notches being adapted to have their respective actions reversed when the movements Yof the breech block proper-and iiring pin carrier are reversed, means for driving back said ilring pin carrier upon the ring of a shot, and spring means interposed between said breech block and said iiring pin carrier for constantly urging said firing pin carrier frontwardly with respect to said breech block.

4. An automatic rearm which comprises, in combination, a tube, a breech structure movable `with a reciprocating motion in line with said tube at the rear thereof, a stationary casing rigid with said tube for guiding said breech structure. said breech structure including a breech block proper provided with a longitudinally elongated transverse slot, two longitudinal bars slidable on either side of said breech block in the longitudinal direction, a transverse member carrying a ring pin and rigidly interconnecting said two bars extending through said slot, whereby the whole of said bars and said transverse member can slide longitudinally to a limited extent with respect to said breech block, cooperating means provided on said breech block proper, said bars and said breech casing and operative by relative displacements of said breech block proper, bars and breech casing, for interlocking said breech block and said bars as long as said breech block has not reached its extreme position toward the 'front and locking said breech. block in said casing when said position is reached While simultaneously uncoupling' said bars from said breech block, whereby said bars and said transverse member can further move frontwardly, said last mentioned means being adapted to have said actions reversed for reversed directions of movement of said breech block proper and bars, means for driving back said bars and said transverse member upon the rlng of a shot, a counterspring for urging said bars and transverse member frontwardly, said bars being provided with longitudinal slots, lugs canied by said breech block engaging in said last mentioned slots respectively, and Asprings housed in said slots between the front ends of said slots and said lugs respectively for constantly urging said bars frontwardly with respect to saidbreech block.

MARC BIRK'IGT. 

